From owner-freebsd-stable@FreeBSD.ORG Thu Aug 16 16:31:34 2007 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 6666316A468; Thu, 16 Aug 2007 16:31:34 +0000 (UTC) (envelope-from SRS0=57cbad3a1054abf23a9641356120c384c11cf931=429=es.net=oberman@es.net) Received: from postal1.es.net (postal2.es.net [IPv6:2001:400:14:3::7]) by mx1.freebsd.org (Postfix) with ESMTP id CCB4613C45E; Thu, 16 Aug 2007 16:31:33 +0000 (UTC) (envelope-from SRS0=57cbad3a1054abf23a9641356120c384c11cf931=429=es.net=oberman@es.net) Received: from ptavv.es.net (ptavv.es.net [198.128.4.29]) by postal2.es.net (Postal Node 2) with ESMTP (SSL) id VYV96232; Thu, 16 Aug 2007 09:31:32 -0700 Received: from ptavv.es.net (ptavv.es.net [127.0.0.1]) by ptavv.es.net (Tachyon Server) with ESMTP id BCBFF45048; Thu, 16 Aug 2007 09:31:32 -0700 (PDT) To: Eugene Grosbein In-Reply-To: Your message of "Thu, 16 Aug 2007 22:38:23 +0800." <20070816143823.GA92480@svzserv.kemerovo.su> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_1187281892_88326P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Date: Thu, 16 Aug 2007 09:31:32 -0700 From: "Kevin Oberman" Message-Id: <20070816163132.BCBFF45048@ptavv.es.net> Cc: Artem Kuchin , freebsd-stable@freebsd.org, Roman Bogorodskiy Subject: Re: panic after removing usb flash disk X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 16 Aug 2007 16:31:34 -0000 --==_Exmh_1187281892_88326P Content-Type: text/plain; charset=us-ascii Content-Disposition: inline > Date: Thu, 16 Aug 2007 22:38:23 +0800 > From: Eugene Grosbein > Sender: owner-freebsd-stable@freebsd.org > > On Thu, Aug 16, 2007 at 04:46:11PM +0400, Roman Bogorodskiy wrote: > > > It's not a bug, it's a feature. > > Kernel panic just cannot be a feature, and other OSes do not > panic this way. Is is design problem and it _is_ the bug > (the hard-to-fix one). It is NOT a bug as FreeBSD is operating as designed and documented. It is a "mis-feature" that resulted from a change in an underlying paradigm of the file system design. When it was developed, no one thought of trivially removable storage like USB and Firewire drives or even hot-pluggable (S)ATA. Unfortunately, when something this fundamental changes, an amazing amount of code has become intertwined in no longer valid assumptions and a redesign based on modern, valid assumptions is a lot of work. Because it involves some of the most complex structures in the system, it is very unlikely that any one person can fix this. It will take a concerted effort by a group with members reasonably expert in each of the parts to the kernel that tie in to the old assumptions and, in a volunteer effort like OSS, all of them need to be able to dedicate time and resources that may conflict with day jobs. While not on the same scale, it is not dissimilar to the SMP redesign effort that so greatly delayed V5 and made it a rather painful version for some people to run. To further complicate things, many of the major contributors to FreeBSD are only interested in it for its use as a server or embedded OS. This means that they are willing to commit resources to SMP, which they need, but not so willing for hot-removal of storage, which is of only slight value in the server and embedded OS world. I am sure that a lot of people who have no professional interest in fixing this do have a strong personal interest and I suspect that it will happen before too long, but complaining about it is not really going to help as almost every FreeBSD desktop and mobile user has been bitten by this at one time or another and wants it fixed. -- R. Kevin Oberman, Network Engineer Energy Sciences Network (ESnet) Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab) E-mail: oberman@es.net Phone: +1 510 486-8634 Key fingerprint:059B 2DDF 031C 9BA3 14A4 EADA 927D EBB3 987B 3751 --==_Exmh_1187281892_88326P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (FreeBSD) Comment: Exmh version 2.5 06/03/2002 iD8DBQFGxHvkkn3rs5h7N1ERAlDcAJ9aVJWESt4GqNjcq9hSgpd8HTnHVQCfQiHO mATriB0ybzMzn7IQ8XgKbM4= =r1wK -----END PGP SIGNATURE----- --==_Exmh_1187281892_88326P--